// Sandstorm - Personal Cloud Sandbox
// Copyright (c) 2016 Sandstorm Development Group, Inc. and contributors
// All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

function fillUndefinedForChangedDoc(newDoc, oldDoc) {
  // In publishes, setting a field to `undefined` specifies that it is no longer present.
  // Annoyingly, in the changed callback of observing a collection, it does not do this for you.
  Object.keys(oldDoc).forEach(function (key) {
    if (!(key in newDoc)) {
      newDoc[key] = undefined;
    }
  });
}

export { fillUndefinedForChangedDoc };
